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A293063 Triangle read by rows (n >= 0, 0 <= k <= n): T(n,k) = number of k-dimensional magnetic subperiodic groups in n-dimensional space, counting enantiomorphs. 3
2, 5, 7, 31, 31, 80, 122, 394, 528, 1651, 1202 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Magnetic groups are also known as antisymmetry groups, or black-white, or two-color crystallographic groups.

T(n,0) count n-dimensional magnetic crystallographic point groups, T(n,n) count n-dimensional magnetic space groups. The name "subperiodic groups" is usually related to the case 0 < k < n only, i.e., magnetic groups of n-dimensional objects including k independent translations which are subgroups of some n-dimensional magnetic space groups.

The Bohm-Koptsik symbols for these groups are G_{n,k}^1, except for the case k=n, when it is G_n^1.

T(2,1) are band groups.

T(3,3) are Shubnikov groups.

For T(n,0) and T(n,n), see [Souvignier, 2006, table 1]. For rows 1-3, see Litvin.

LINKS

Table of n, a(n) for n=0..10.

H. Grimmer, Comments on tables of magnetic space groups, Acta Cryst., A65 (2009), 145-155.

D. B. Litvin, Magnetic Group Tables

B. Souvignier, The four-dimensional magnetic point and space groups, Z. Kristallogr., 221 (2006), 77-82.

Index entries for sequences related to groups

EXAMPLE

The triangle begins:

     2;

     5,   7;

    31,  31,  80;

   122, 394, 528, 1651;

  1202, ...

CROSSREFS

Cf. A293060, A293061, A293062.

Sequence in context: A192560 A174288 A293062 * A215211 A118786 A083777

Adjacent sequences:  A293060 A293061 A293062 * A293064 A293065 A293066

KEYWORD

nonn,tabl,hard,more

AUTHOR

Andrey Zabolotskiy, Sep 29 2017

STATUS

approved

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Last modified October 22 09:57 EDT 2018. Contains 316433 sequences. (Running on oeis4.)